HtmlSidebar

Allow admin to post some html code or javascript onto the right sidebar.

I'm wondering how hard it would be to write a component that would
allow us to insert HTML on the sidebars (left or right). It
could be useful for posting site news messages or widgets. Would it be
too difficult to do something like that?

Using this component you'll get idea about:

1. How to add new action
2. How to create component settings page
3. How to add content on right sidebar of newsfeed page.

Changes:

V 5.1
Fixed the mobile issue , thanks to Michael for fixing it.

V 5.0
Allow JS/CSS tags

V 4.3
A configurable option has been added to display the sidebar content on top of the newsfeed on mobile devices

V 4.2
Comes with a WYSIWYG editor now to allow more comfortable editing.
Of course you may still add your own plain html and/or javascript by choosing "Tools -> Source Code" from the editor menu top right like: